High Quality $\mathrm{TE}_{011}$ Mode Cavity Filter for Input Multiplexer Applications

This paper presents a novel resonator realized by chamfering the edges of a square cavity, and the high quality factor (Q) TE011 mode can be separate from its degenerate TM111 mode. Detailed analysis of the coupling mechanisms among the resonators is demonstrated, which can conveniently achieve complicated transfer functions. Based on the typical specification of Ka-band input multiplexer (IMUX), two channel filters utilizing the novel resonator are designed and fabricated with 60MHz bandwidth centers on 20GHz and 20.3GHz respectively. The measured responses show excellent agreement with the simulation. Average realizable unloaded Q of 10500 can be achieved.